System for Controlling Variable Valve

ABSTRACT

A system for controlling variable valve includes a crank angle sensor detecting an angle of a crankshaft, an engine control unit (ECU) (ECU) outputting a control signal to the intake and exhaust valves by receiving a sensing signal from the crank angle sensor, a control portion transmitting the signal input from the engine control unit (ECU), a first valve comprising a first actuator controlling the intake valve and a second valve comprising a second actuator controlling the exhaust valve wherein each actuator receives the signal from the control portion, a pressure supply unit supplying pressure to the first and second valves, and first and second sensors detecting positions of the actuators, wherein the control portion compensates the operation error of actuators by receiving the feedback signal from the first and second sensors. By controlling variable valve, the intake and exhaust valves may be precisely controlled and fuel consumption can be improved.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2006-0128187 filed in the Korean Intellectual Property Office on Dec. 14, 2006, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a system for controlling variable valve and more particularly, to a system controlling variable valve not utilizing a cam.

(b) Description of the Related Art

Typically, a variable valve system improves fuel consumption and output of an engine and reduces exhaust gas by controlling a phase, an operating angle, and a lift of an intake valve and an exhaust valve.

According to the prior art, a mechanical variable valve system controls the phase, operating angle, and lift of the valve by mechanically controlling a position of a cam or a shaft.

On the other hand, in a case of a camless variable valve system not utilizing the cam mechanism but utilizing hydraulic pressure and electronic control, a problem occurs that the system is difficult to be disposed in an engine room because of its complicated scheme.

In addition, in a case of the camless variable valve system, another problem occurs that the operation thereof is unstable.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide system for controlling variable valve having advantages of stable operation and improving fuel consumption.

An exemplary embodiment of the present invention provides a system for controlling variable valve controlling intake and exhaust valves of an engine, including a crank angle sensor detecting an angle of a crankshaft, an engine control unit (ECU) outputting a control signal to control the intake and exhaust valves by receiving a signal from the crank angle sensor, a control portion transmitting the signal input from the engine control unit (ECU), a first valve comprising a first actuator opening and closing the intake valve by receiving the signal from the control portion, a second valve comprising a second actuator opening and closing the exhaust valve by receiving the signal from the control portion, a pressure supply unit supplying pressure to the first and second valves, and first and second sensors detecting positions of the first and second actuators, wherein the control portion compensates the position errors of the first and second actuators by receiving the feedback signal from the first and second sensors.

The system for controlling variable valve controlling intake and exhaust valves may further include a waveform generator transforming the control signal input from the engine control unit (ECU).

The system for controlling variable valve controlling intake and exhaust valves may further includes a first amplifier unit amplifying the signal transmitted from the control portion and a second amplifier unit amplifying the feedback signal transmitted from the first and second sensors.

The first and second sensors may be realized as a Differential Transformer (DTF) sensor.

The engine control unit (ECU) may output the control signal on the basis of a clock signals input from outside.

The above features and advantages of the present invention will be apparent from or are set forth in more detail in the accompanying drawing, which is incorporated in and form a part of this specification, and the following Detailed Description of the Invention, which together serves to explain by way of example the principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present invention will now be described in detail with reference to certain exemplary embodiments thereof illustrated in the accompanying drawing which is given hereinbelow by way of illustration only, and thus is not limitative of the present invention, and wherein:

FIG. 1 shows a system for controlling variable valve according to an exemplary embodiment of the present invention.

It should be understood that the appended drawing is not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to an embodiment of the present invention, example of which is illustrated in the accompanying drawing and described below. While the invention will be described in conjunction with exemplary embodiment, it will be understood that present description is not intended to limit the invention to the exemplary embodiment. On the contrary, the invention is intended to cover not only the exemplary embodiment, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims

FIG. 1 shows a system for controlling variable valve according to an exemplary embodiment of the present invention.

As shown in FIG. 1, according to an illustrated exemplary embodiment of the present invention, a system for controlling variable valve controlling intake and exhaust valves of an engine includes a crank angle sensor 101, an engine control unit (ECU) 105, a control portion 123, a first valve 109, a second valve 111, a pressure supply unit 117, a first sensor 119, and a second sensor 121.

The crank angle sensor 101 detects an angle of a crankshaft (not shown) and the engine control unit (ECU) 105 outputs a control signal to control the intake and exhaust valves 125 and 127 by receiving a sensing signal from the crank angle sensor 101.

The control portion 123 receives the control signal from the engine control unit (ECU) 105 and transmits the same.

The first and second valves 109 and 111 include the first and second actuators 113 and 115 to open and close the intake and exhaust valves 125 and 127 by receiving the signal input from the control portion 123.

The control portion 123 may be realized as at least one microprocessor operated by a predetermined program.

The pressure supply unit 117 supplies pressure to the first and second valves 109 and 111.

The first and second sensors 119 and 121 detect positions of the first and second actuators 113 and 115.

The control portion 123 receives the feedback signal from the first and second sensors 119 and 121 and compensates position errors of the first and second actuators 113 and 115.

As shown in FIG. 1, the engine control unit (ECU) 105 receives sensing signal of the crank angle sensor 101 corresponding to a clock signals input from outside.

That is, the engine control unit (ECU) 105 receives the sensing signals from the crank angle sensor 101 at a constant time interval.

The engine control unit (ECU) 105 transmits a control signal to the control portion 123 and according to an exemplary embodiment of the present invention, the system for controlling variable valve further includes waveform generator 107 transforming the control signal transmitted from the engine control unit (ECU) 105 and transmits a voltage signal to the control portion 123 through the waveform generator 107 and then, the control portion 123 transmits the signal to the first and second valves 109 and 111.

The first and second valves 109 and 111 change a phase, an operating angle, and a lift of the intake and exhaust valves 125 and 127 corresponding to the signal of the control portion 123.

That is, according to an exemplary embodiment of the present invention, mechanical elements, i.e., constituent elements such as a cam or a camshaft, are not utilized and the intake and exhaust valves 125 and 127 are variably controlled by which the magnitude of the current applied to the first and second valves 109 and 111 is controlled.

Therefore, the intake and exhaust valves 125 and 127 may be freely controlled corresponding to a variable status and the engine.

The first and second valves 109 and 111 include the first and second actuators 113 and 115 and the intake and exhaust valves 125 and 127 are operated by the first and second actuators 113 and 115.

In addition, the first and second valves 109 and 111 control a speed of the first and second actuators 113 and 115 by controlling a fluid amount supplied from the pressure supply unit 117.

Therefore, because the phase, operating angle and lift of the exhaust valve 127 are controllable, fuel consumption may be improved and contamination may be reduced.

The positions of the first and second actuators 113 and 115 are detected by the first and second sensors 119 and 121.

That is, the position of the first actuator 113 is detected by the first sensor 119 and the position of the second actuator 115 is detected by the second sensor 121.

The signals related to the first and second actuators 113 and 115 detected by the first and second sensors 119 and 121 are input to the control portion 123.

The first and second sensors 119 and 121 may be realized as a Differential Transformer (DTF) sensor.

The control portion 123 calculates if operation error of the intake and exhaust valves 125 and 127 occurs by comparing a target value for controlling the intake and exhaust valves 125 and 127 with the feedback signal of the first and second sensors 119 and 121.

At that time, if the operation error occurs, the control portion 123 outputs the signal to the first and second valves 109 and 111 with compensating the operation error.

Therefore, according to an exemplary embodiment of the present invention, the intake and exhaust valves 125 and 127 may be more precisely controlled.

In addition, because mechanical friction and power loss due to an inertia of a mass are reduced by not using the cam, operating responsiveness can be improved and degree of freedom of timing and the lift of the intake and exhaust valves 125 and 127 can be improved.

On the other hand, according to an exemplary embodiment of the present invention, the system for controlling variable valve further includes a first amplifier unit 129 amplifying the signal transmitted from the control portion 123 and a second amplifier unit 131 amplifying the feedback signal of the first and second sensors 119 and 121.

According to an exemplary embodiment of the present invention, the intake and exhaust valves can be more precisely controlled and degree of freedom of the valve can be improved.

In addition, because the scheme thereof is simple, efficiency of a space of an engine room may be improved. Since a cam is not used, mechanical friction and power loss due to an inertia of a mass are reduced and thus, operating responsiveness can be improved.

While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. 

1. A system for controlling variable valve controlling intake and exhaust valves of an engine comprising: a crank angle sensor detecting an angle of a crankshaft; an engine control unit outputting a control signal to control the intake and exhaust valves by receiving a sensing signal from the crank angle sensor; a control portion transmitting the control signal input from the engine control unit (ECU); a first valve comprising a first actuator opening and closing the intake valve by receiving a signal from the control portion; a second valve comprising a second actuator opening and closing the exhaust valve by receiving a signal from the control portion; a pressure supply unit supplying pressure to the first and second valves; and first and second sensors detecting positions of the first and second actuators, wherein the control portion compensates position errors of the first and second actuators by receiving feedback signal from the first and second sensors.
 2. The system of claim 1, further comprising at least a waveform generator transforming the control signal input from the engine control unit (ECU).
 3. The system of claim 1, further comprising: a first amplifier unit amplifying the signal transmitted from the control portion; and a second amplifier unit amplifying the feedback signal transmitted from the first and second sensors.
 4. The system of claim 1, wherein the first and second sensors are realized as Differential Transformer (DTF) sensor.
 5. The system of claim 1, wherein the engine control unit (ECU) outputs the control signal on the basis of a clock signals input from outside. 